Tangible Bytes

A Web Developer’s Blog

Firebase Emulator Add Users

I’ve been using Google’s Firebase recently and find it a great development platform.

One of the best things about it is the emulators available for local development.

Just a few weeks ago they made it even better by adding an authentication emulator

So now you can easily start up a clean environment to test your new code on.

But the auth emulator starts with no users every time.

This is one way to add users.

  • Add the following to your functions/index.js file
  • Adjust the users section as needed.
  • When you start the emulator request the page
  • http://localhost:5001/${your_project}/us-central1/populateAuthUsers

exports.populateAuthUsers = functions.https.onRequest(async (req, res) => {
  if (!process.env["FUNCTIONS_EMULATOR"]) {
    return res
      .send("ACCESS DENIED. This function is ONLY available via an emulator");
  const users = [
      uid: "user1",
      displayName: "one Local Admin",
      email: "one@test.com",
      password: "password",
      uid: "user2",
      displayName: "two Local Admin",
      email: "two@test.com",
      password: "password",
    // put all test users you want populated here

  const results = [];
  const promises = [];
  for (let user of users) {
    let promise = admin
      .then((result) => {
        return result;
      .catch((error) => {
        return error.message; // continue on errors (eg duplicate users)

Firestore data

If you need firestore data as well just export what you need

firebase emulators:export ./emulator-data/

and start the emulator with an import

firebase emulators:start --import=./emulator-data/

Hopefully this will include auth data too in the future